Arrangement for changing over the speaking direction in loud-speaker duplex systems



Feb. 1, 1949. o. TSCHUMI 2,460,475

- ARRANGEMENT FOR CHANGING-OVER THE SPEAKING DIRECTION IN LOUD-SPEAKER DUPLEX SYSTEMS Filed May 12, 1944 Patented Feb. 1, 19 49 ARRANGEMENT FOR CHANGINGoVER THE SPEAKINGDIRECTION lN- ILOUD-SPEAKER DUPLEX SYSTEMS t-to' Tschumi, Soleure, Switzerland, assignor' to I 'Autophen; Aktiengesellschait, -S

.zerland, a joint-stock compan u wi Switzerland ApplicationMay 12, 1944-,'-Seri-aI Nc..535,29? In Switzerland December 4', 19.42.

The invention relates to arrangements for changing over the speaking direction in. loud pea rrdunlexsystem The determination of the speaking direction in loud speaker duplex systemswas. hitherto effected by an additional key which, in most cases, was

adjoi'ned to the station establishin the connection and which remained in operating position as long as a certain speaking direction was desired.. The changing-over of the speaking direction was carried out by lettingthe; key go.

3 Thez 'great disadvantage of,-.this.fdevice-consists in ,the-"factl t'hat' "this" changingeover could be enacted membranes bungee thatin this station alone it wasjpossibletechangethe speakingdirectionl ing therefrom was unsuitable for many purposes and it was, therefore, desired to, create a changing-over arrangement guaranteeing a complete coordination of the subscribers stations.

Object of the present invention is an arrangement for changing-over loud speaker duplex systems which is characterized in that the changingover is effected by a short-time change of an electric continuous state. This state may be of any kind, that is, it may consist in the fact that a more or less intense current flows through the switch devices, or that the latter are without current. Therefore the short-time change of the electric continuous state consists in a current amplification, a current reduction, a current impulse or an interruption.

The means by the aidof which the changes can be effected are various and are well-known to those skilled in the art.

The accompanying drawings illustrate, by way of example, one embodiment of the object of invention. V

Fig. 1 is a diagram of the subscribers device, while Figs. 2 to 4 illustrate in a diagrammatic way details of the main station.

For effecting a short-time change in the electrical connections, the subscriber desiring to change the speaking direction in the example illustrated dials the number 1 on the existing calling dial, i. e., he interrupts a direct current for a short time. This use of the calling dial has the additional advantage that no further switching devices need be added to the subscribers station in that the existing means are sufficient. 7

Referring now to Fig. 1, the transducer EW is connected withthe terminals a, 11 over the amplifier V which can be alternately switched-in The'rsubor'di'n'ation "er the. stations result- 1 Claim. (01. 139.51

bathe-switches wand uz. The terminals wand b are connected with each other by the impedance coit-Dr. The eentre ofthis coil Dr is earthed dyer the switch e2,a. rectifier arrangement with the relays-1U..-Eiand,the o.ptical signal SZ, and

oyenijhe'im-pulse contact iof the callingdial'NS. .,In Fig. '2 a1, b 1 ,are.the connections tor the calling-and :12, b2, the connections for the. called subscribers station. The centres ,of the transidrniei"windings,. both{on the. side of the called and on the side ei the. calling subscriber, are connected over relay J, switch 8101'. over relay Y,

switch s2 respectively with the negative pole of a non-illustratedbattery earthed en the positive sideor positive .p'ole'o'f a non-illustrated battery earthed on the negative; side. respectively.

Fig. .3, ;illustrates thear'ranglement of a relay controlling. the switches. 81,. s and s3. Thisv relay is, on the one side, connected to the negative pole of a battery earthed on the positive side, and, on the other side, earthed over the switch II and the switches n and '1 connected in parallel.

Fig. 4 shows the circuit of the time-delay relay II controlled by the switches 1/2 and 9'2 connected in series.

When the calling subscriber has established a connection with the called subscriber over a connection established by an automatic exchange, the contacts 61 and eg have been closed in a non-illustrated manner, which, on the one side, results in the switching-in of the amplifier V and, on the other side, in the opening of a direct current path from the middle of the impedance coil Dr over the rectifier arrangement to the earthed contact of the impulse contact 2. The terminals 11, b in Fig. 1 are connected over pre-selectors or call finders or other selectors with the terminals 0,2, In in Fig. 2 and the terminals of the nonillustrated called station. The establishment of these operating conditions results in the following direct current: earth-impulse contact i-rectifier arrangement and relays E and U-e2- impedance coil Dr-terminals a, bterminals a1, br-relay J-contact si-rnegative pole of a battery earthed on the positive side. The result .is that, on the one hand, relay E continues in action, i. e., the contacts c1 and 62 remain closed and that, on the other hand, relay U also comes into action. Thereby, the switches in and in are actuated, and the calling station is connected for hearing. On the opposite side (the called station) a similar direct current circuit, but in reversed direction, isformed, so that, contrary to the first-named circuit, relay U is now shortcircuited by a rectifier element and, for this 3 reason, remains without current, While, in its place, the optical signal s2 is inserted into the circuit and flashes up, indicating in this Way that th s station is in speaking condition.

Now the speaking direction can at will be changed by the calling or the called party by dialling the number 1 on the calling dial. If it is, for instance, the person calling who actuates the dial in the manner aforesaid, the impulse con-' tact is interrupted for a short time and the sparking contact 7c short-circuited during the selecting process. The short-time interruption of the current in the previously mentioned circuit of the calling station does not result in a dropping of the relays U and E which is delayed by the parallel connection of rectifier elements, but only in a dropping of relay J. This dropping closes the circuit of the switch relay S in Fig.3which, in its turn, operates the contacts s1, s2 and .93. By

the operation of the contacts s1 and $2, the centres of the transformer Tr are connected to the positive pole of a, power source earthed on the negative side, and to the negative pole of a power source earthed on the positive side. This results in the formation of the following circuit on the calling station: p1us--s1re1ay J-terminals a1, b1termihals a, b--impe'dance coil Dr-contact ez-rectifier arrangementoptical sign SZ and relay Eimpu1se contact 2 and earth. The relay U short-circuited by a rectifier element, and its switches ui, uz, drop and the subscribers device illustrated is again changed-over for use in speaking such condition being indicated by a flashingup of the optical signal SZ.

- The reverse takes place on the side of the station called which, in its turn, is now changed-over to the hearing position.

The conversation being terminated, the contact s3 serves the purpose of bringing the relay Number S back into initial position provided that this is not already the case. What I claim is:

In a loud speaker duplex system comprising several subscribers stations, an arrangement for changing over the speaking direction including a transducer and a dial in each Of said sub scribers stations, dial contacts operated by the dial, a relay arrangement, a battery, contacts for connecting a subscriber station, contacts for changing over the speaking direction, a rectifier arrangement, a bridge relay in said rectifier arrangement operating said contacts for connect ing a subscriber station, a shunt relay shunting a part of said rectifier arrangement and oper- REFERENCES CITED The following references are of record in the file of this patent:

V UNITED STATES PATENTS Name Date 2,044,305 Johnson June 16, 1936 2,102,903 Leveque Dec. 21, 1937 2,192,540 Creti Mar. 5, 1940 2,214,804 Augustadt Sept. 17, 1940 2,224,698 Roseby Dec. 10, 1940 2,249,456 Campbell July 15, 1941 2,369,144 Herrick]. Feb. 13, 1945 2,369,351 Herrick Feb. 13, 1945 

